The present invention relates to a new and distinct cultivar of Hydrangea macrophylla and will be referred to hereafter by its cultivar name, ‘Youme H1917’. ‘Youme H1917’ represents a new bigleaf hydrangea, a perennial shrub grown for landscape use.
‘Youme H1917’ was derived from an ongoing controlled breeding program by the Inventor that focuses on developing new cultivars of bigleaf hydrangeas with unique flower colors and double flowers. ‘Youme H1917’ originated from a cross conducted in the Inventor's trial garden in June 1996 in Kyoto, Japan between an unnamed plant of Hydrangea macrophylla from the Inventor's breeding collection as the female parent and Hydrangea macrophylla ‘Yamaajisai’ (not patented) as the male parent. The new Hydrangea was selected as a unique single plant from the progeny of the cross in 2000.
Asexual reproduction of the new cultivar was first accomplished by softwood stem cuttings in Kyoto, Japan in 2000 by the Inventor. The characteristics of this cultivar have been determined to be stable and are reproduced true to type in successive generations.